Retaining-valve.



l CE. E. MARTN.

RETAINING VALVE.

APPLIoA'rIoN FILED Nov. as, 1911.

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P. E. MARTN.

RETAINING VALVE. n APPLICATION FILED NOV. 28, 1911.

1,048, 122. Patented Nov. 5, 1912.

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' all 'lnlll--Iellllllllh I UNITED sTATEs PATENT oEEIoE.

FREDERICK E. MARTIN, or BONAMI, LOUISIANA.

Specification of Letters Patent.`

Patented Nov. 5, 1912 Application lied November28, 1911. Serial No.662,885.

To all whom t may concern."

in the art to which it appertains to make and use the same.

This Invention relates to new and useful improvements in retainingvalves to be used I in connection with the existing air-brake systems,and has for its object to provide devices of that nat-ure which will besimple in operation, comparatively inexpensive,`

and which will not readily get out of order. With these and otherobjects` in 'view .the invention consists in the novel details ofconstruction and combinations of parts more fully hereinafter disclosedand pointed out in the claims.

Referring to the accompanying drawings forming a part of thisspecification in which like numerals refer to like parts in all theparticularly views Figure 1 is a vertical section of my Y invention;Fig. 2, a section view of some of the parts shown in Fig. 1, but havingthe double piston inverted; Fig.` 3, a vertical section view of aslightly modified form.

My invention as shown in Fig. 1 cor'lprises a casing 1, the lower partof which connects at 2 with the train pipe or with the usual auxiliaryreservoir. The casing is adapted to provide the chambers 3, 4 and 5, ofwhich the chambers 4 and 5 have a communicating passage 6.

Located within the chambers 3 and 4 is a double piston 7 having thepacking rings 3 and 9. A rod 10 is provided within the communicatingpassage 6 which has mounted on it a valve 11 adapted to seat in therecess 12. Seated against the member 11 is a collar 13 against whichrests a spiral spring 14, the other end of which bears against a similarcollar 15. The end 16 of the I'od 10 rides in a groove 17 in theadjusting screw 18 which regulates the tension of the spring14.Connected to the casing 1 is an exhaust pipe 19 of a triple valve, notshown in the drawing. 2O is the ordinary exhaust. It is thereforeevident that when the train pipe air is suliicient to overcome thespring 14 air passes through the aperture 21 in the plug 22 screwed in`the end' of the casing 1, and acts upon` the lower ,face 2G of thedifferential piston .7 to start said piston upward. After thedifferential piston has thus moved upwardly a-suiicient distance touncover the lower ends of the groove 23, Lthe air will pass throughthegrooves 23, 24 and 25, andact upon'both` faces 26 and 27 of said piston,thereby causing a sudden shifting of said piston to its upper position,as shownin Fig. 1. Consequentlyy the rod 10 will be moved upwardly bythe piston to cause an advantageously quick opening of the valve 11; thecollar 13 being pressed upwardly against the tension of the spiralspring 14. This operation allows of the exhaust from the pipe 19 toenter the casing passing around the rod-10 through the outlet 20 to theatmosphere.

Whenthe train pipe pressure is reduced for any reason, such-as when thebrakes are applied,` the` spring 14 overcomes the resistance of thetrain pipe pressure against the faces 26 and 27, and forces collar 13downwardlyA seat-ing the' member 11 against its seat 12, also forcingthe rod 1() and consequently the piston 7 against the screwplug 22.During the initial movement of the piston 7 ,fthe enlarged portion 27thereof willuncover theA upper end of the groove 25, whereupon the airwill be free to escape from beneath both faces 26 and 27 of said pistonthrough the grooves v23, 24 and 25 and the passages 6 and 2O to theatmosphere. This causes the triple-valve exhaust to be cut off, andretains the brake cylinder pressure until the train pipe pressure shouldagain become sufficient to overcome the spring 14, resulting in theprevious opera.- tionvand opening the triple exhaust.4

The two operating pressures of this retaining valve are regulated bythedifference in size of the ends of the piston. This piston in Fig. 2is shown in elevation and also of the inverted type having the grooves23 and 25 located within the casing 1. manner of the operation oftheparts in Fig. 2 is the same/as the operation in Fig. 1.

In vFig.` 3 the pressure from thetrain pipe 30` passes through theperforations 31 in The the `screw-plug 32, and channel 33, tothe Y fromthe triple valve pipe 39 to pass through the passage 40 connecting thechambers 4l and 42 through the passage 43 to air. Vhen pressure from thetrain pipe gets below a prearraiiged amount the spiral spring 44 in thechamber 45, operating between the extension 46 and collar 47, held onthe rod 35 by a nut 48, withdraws the stem 35, and permits the valve 37to be seated by a spring 49 mounted upon the rod 50 on the stem 51 ofthe valve 37 and located in t-he recess 52 in a scre'w plug 53; therebyshutting oii the flow of exhaust from the triple valve pipe 39. Shouldthe pressure become still lower the spiral spring 44 forces diaphragm 34farther down, thus seating the lower part of rod 35 uponits seat 36 anddraws the upper end 54 of rod 35 away from the valve 37, causing the airpressure `in chamber 42 to exhaust to atmosphere. "With the pressure outof chamber 42 the train pipe pressure is ett'ective only against thesmaller diaphragm 55, and consequently it will take a much higherpressure to open the valve than that at which it closed. 56 is aperforation which connects the chamber 42 with the channel 33 of the rod35.

It is therefore evident from all forms shown that with this valveattached to the ordinary air-brake equipment the engineer can, byworking his train pipe pressure below a pre-arranged amount, close thetriple exhausts on each car and the brakes will stay set until the trainpipe and auxiliaries have been recharged to a pre-arranged pressure,when the retaining valve will open and allow brakes to release, and withthe train pipe and auxiliaries charged the brakes are ready to setagain. The engineer can when the train pipe is only partially rechargedset brakes by causing a reduction in train pipe pressure, just the samewith this retaining valve in action as not in action.

It is obvious that those skilled in the art may vary the details ofconstruction and the arrangement of parts without departing from thespirit of my invention.

lVhat I claim is l. In an air-brake mechanism, a casing providingchambers, one of said chambers connecting with the train pipe; a doublepiston operable in two of said chambers and exposed to train pipepressure; a valve in another of said chambers; connections between thedouble piston and valve; a triple valve pipe communicating with saidvalve chamber; and exhaust passages coinmunicating with said piston andvalve chambers, substantially as described. v

2. In an air-brake mechanism, a casing providing chambers, one of saidchambers connecting with the train pipe; a double pist0n operable in twoof said chambers and exposed to train pipe pressure; a valve iii anotherof said chambers; a spring for normally holding said valve seated;connections between the double piston and valve; a triple valve pipecommunicating with said valve chamber; and exhaust passagescommunicating with said piston aiid valve chambers, substantially asdescribed.

3. In an air-brake mechanism, a casing providing chambers, one of saidchambersl connecting with the train pipe; a double piston of differentdiameters operable in adjacent chambers and exposed to train pipepressure; a valve in the other of said chambers; a spring for normallyholding said valve seated; connections between the double piston andvalve; a triple valve pipe coniinunicating with said valve chamber; andexhaust passages communicating with said piston and valve chambers,substantially as described.

4. In an air-brake mechanism, a casing providing chambers, one of saidchambers` connecting with the train pipe; a double piston of diiferentdiameters operable in adjacent chambers and exposed to train pipepressure; said casing having its walls constructed to provide apassageway between said double piston chambers; a valve in the other ofsaid chambers; a spring for normally holding` said valve seated;connections between the double piston and valve; a triple valve pipecommunicating with said valve chamber; and exhaust passagescommunicating with said piston and valve chambers, substantially asdescribed.

5. In an air-brake mechanism, a casing p foviding chambers, one of saidchambers cnnecting with the train pipe; a double piston of differentdiameters operable in adjacent chambers and exposed .to train pipepressure; said casing having its walls constructed to provide apassageway between said double piston chambers; a valve in the other ofsaid chambers; a spring for -normally holding said valve seated;`anadpisting screw for regulating the tension of said spring; connectionsbetween the double piston and valve; a. triple valve pipe communieatingwith said valve chamber; and exhaust passages communicating with saidpiston and valve chambers, substantially as described.

In testimony whereof, I aiiix my signature, in presence of twowitnesses.

FREDERICK E. MARTIN.

Witnesses J. M. WARREN, W. C. STEWART.

Copies of this patent may be obtained for ive cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

